Impact indicator

ABSTRACT

A device and technique for impact detection includes a tube having a first fluid and a second fluid disposed therein, wherein a viscosity of the second fluid is greater than a viscosity of the first fluid, and wherein, responsive to a predetermined level of impact received by the impact indicator, at least a portion of the first fluid mixes into the second fluid to create a change in color of the second fluid to provide a visual indication of the received impact.

BACKGROUND

During manufacturing, storage or transit, many types of objects need tobe monitored due to the sensitivity or fragility of the objects. Forexample, some types of objects may be susceptible to damage if droppedor a significant impact is received. Thus, for quality control purposesand/or the general monitoring of transportation conditions, it isdesirable to determine and/or verify the environmental conditions towhich the object has been exposed.

BRIEF SUMMARY

According to one aspect of the present disclosure, a device andtechnique for impact detection and indication is disclosed. The impactindicator includes a tube having a first fluid and a second fluiddisposed therein, wherein a viscosity of the second fluid is greaterthan a viscosity of the first fluid, and wherein, responsive to apredetermined level of impact received by the impact indicator, at leasta portion of the first fluid mixes into the second fluid to create achange in color of the second fluid to provide a visual indication ofthe received impact.

According to another embodiment of the present disclosure, an impactindicator includes a tube; a first fluid disposed within the tube; asecond fluid disposed within the tube, and a third fluid disposed withinthe tube, wherein the third fluid is disposed between and separates thefirst fluid from the second fluid in a non-activated state of the impactindicator. In response to a predetermined level of impact received bythe impact indicator, at least a portion of the first fluid contacts thesecond fluid to create a change in color of the second fluid to providea visual indication of the received impact

According to another embodiment of the present disclosure, a method formanufacturing an impact indicator includes: disposing, within a tube, afirst fluid; disposing, within the tube, a second fluid spaced apartfrom the first fluid by a third fluid, the second fluid selected havinga viscosity greater than a viscosity of the first fluid. Responsive to apredetermined level of impact received by the impact indicator, at leasta portion of the first fluid contacts the second fluid to create achange in color of the second fluid to provide a visual indication ofthe received impact.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

For a more complete understanding of the present application, theobjects and advantages thereof, reference is now made to the followingdescriptions taken in conjunction with the accompanying drawings, inwhich:

FIG. 1A is a diagram illustrating an application of embodiment of animpact indicator according to the present disclosure;

FIG. 1B is a diagram illustrating an enlarged view of the impactindicator of FIG. 1A;

FIG. 2 is a diagram illustrating a tube assembly of the impact indicatorof FIGS. 1A and 1B in a non-activated state according to the presentdisclosure;

FIG. 3 is a diagram illustrating the tube assembly of FIG. 3 in responseto exposure to an acceleration event in accordance with the presentdisclosure;

FIG. 4 is a diagram illustrating an impact activation zone correspondingto various embodiments of an impact indicator according to the presentdisclosure; and

FIG. 5 is a diagram illustrating another embodiment of an impactindicator according to the present disclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure provide a device and technique forimpact detection and indication. According to one embodiment, an impactindicator includes a tube having a first fluid and a second fluiddisposed therein, wherein a viscosity of the second fluid is greaterthan a viscosity of the first fluid, and wherein, responsive to apredetermined level of impact received by the impact indicator, at leasta portion of the first fluid contacts the second fluid to create achange in color of the second fluid to provide a visual indication ofthe received impact. Embodiments of the present disclosure enable impactand/or acceleration event detection and indication utilizing a passive,small/compact indicator. Impact activation levels may be obtained over avariety of acceleration levels experienced for certain time durations byselecting a certain internal cavity size of the tube and/or certainviscosity levels of fluids contained with the tube.

With reference now to the Figures and in particular with reference toFIGS. 1A and 1B, exemplary diagrams of an impact indicator 10 areprovided in which illustrative embodiments of the present disclosure maybe implemented. In FIGS. 1A and 1B, impact indicator 10 is a portabledevice configured to be affixed to or disposed within a transportcontainer containing an object of which impact and/or accelerationevents associated therewith are to be monitored. Embodiments of impactindicator 10 monitor whether an object has been exposed to an impact orsome level of an acceleration event during manufacturing, storage and/ortransport of the object. In some embodiments, impact indicator 10 may beaffixed to a transport container using, for example, adhesive materials,permanent or temporary fasteners, or a variety of different types ofattachment devices. The transport container may include a container inwhich a monitored object is loosely placed or may comprise a containerof the monitored object itself. It should be appreciated that FIGS. 1Aand 1B are only exemplary and are not intended to assert or imply anylimitation with regard to the environments in which differentembodiments may be implemented.

FIG. 1A is a diagram illustrating an embodiment of impact indicator 10used in connection with a transport container, and FIG. 1B is a diagramillustrating an enlarged view of a portion of impact indicator of FIG.1A. In the embodiment illustrated in FIGS. 1A and 1B, impact indicator10 is configured to detect and indicate impact or acceleration eventsrelative to indicator 10. For example, referring to FIG. 1A, impactindicator 10 comprises a clip assembly 12 that is affixed to a container14 for detecting and indicating impact or acceleration events relativeto container 14. As described above, clip assembly 12 may be affixed toan exterior surface of container 14 using, for example, adhesivematerials, permanent or temporary fasteners, or a variety of differenttypes of attachment devices or mechanisms. However, it should also beunderstood that impact indicator 10 may also be located and/or disposedwithin container 14. Clip assembly 12 is configured to support a tubeassembly 16. In some embodiments, clip assembly 12 is configured tosupport tube assembly 16 while enabling an indicating portion of tubeassembly 16 to be visible for visually indicating whether anacceleration event has been experienced/detected. However, it should beunderstood that clip assembly 12 may be otherwise configured. It shouldbe further understood that in some embodiments, tube assembly 16 may beused independently of clip assembly 12. For example, tube assembly 16may be incorporated directly into container 14, located within aninternal or external pocket or holding device of container 14, placedloosely within container 14, or otherwise used without clip assembly 12.

As illustrated in FIG. 1B, clip assembly 12 includes support portion 20and 22 that support opposite ends of tube assembly 16. Support portions20 and 22 are configured to enable an indicating portion 26 of tubeassembly 16 to be visible to enable a user or viewer to visually detectwhether an acceleration event has been experienced by and/or detected byimpact indicator 10. As will be described in further detail below,indicating portion 26 of tube assembly 16 may provide a color indicationof impact detection/indication (e.g., changing from one color to adifferent color). It should be understood that clip assembly 12 may beotherwise configured to facilitate attachment of tube assembly 16 tocontainer 14 and providing a visual indication of impact detection.

FIG. 2 is a diagram illustrating an embodiment of impact indicator 10without clip assembly 12. In the illustrated embodiment, tube assembly12 comprises a tube 30 having a closed end 32 and an open end 34. A plug36 is insertable into open end 34 to seal tube 30. However, it should beunderstood that in some embodiments, tube 30 may be configured withopenings at both ends such that a plug 36 may be inserted at each end toseal an interior portion of tube 30. In the embodiment illustrated inFIG. 2, tube 30 comprises a hollow tube 30 having an internal diameteror cavity 40 for containing fluids therein. For example, in theillustrated embodiment, tube 30 comprises a cylindrical tube having aninternal cavity 40 for containing fluids therein. However, the shape oftube 30 may be otherwise configured/selected. In some embodiments, tube30 comprises a single tube-like structure formed from a clear,transparent, translucent and/or semi-opaque material to enablevisibility of fluids contained within tube 30 (e.g., at least withrespect to indicating portion 26). However, it should be understood thatin some embodiments, tube 30 may be formed from multiple componentsattached together to form tube 30 (e.g., multiple components attachedtogether such that at least one of the components comprises a clear,transparent, translucent and/or semi-opaque portion or window to enablevisibility of a fluid contained within the structure). Tube 30 may alsobe formed from an opaque material but having at least a portion thereof(e.g., a window) to enable visibility of at least a portion of a fluidlocated within tube 30 (e.g., at least with respect to indicatingportion 26). Plug 36 may comprise an epoxy plug/seal or other type ofdevice/component for sealing end 34 and retaining fluids located withininternal cavity 40 of tube 30.

In the embodiment illustrated in FIG. 2, a fluid 50 is located near orat an end 52 of internal cavity 40, and a fluid 54 is located near or atan opposite end 56 of internal cavity 40. Fluids 50 and 54 are spacedapart from each other within cavity 40 in an inactivated state of impactindicator 10 by a separating fluid 58. In some embodiments, separatingfluid 58 comprises a gas such as, but not limited to, atmospheric air,and fluids 50 and 54 are liquids; however, other types of fluids (gasesor liquids) may be used for fluids 50, 54 and 58. In some embodiments,fluid 54 comprises a coloring fluid or dyed fluid, and fluid 50comprises a clear, non-colored, or different color than a color of fluid54 that is soluble or miscible with fluid 54. In some embodiments, fluid54 may include a colored dye such that the colored dye discolors and/orotherwise causes a color change to fluid 50 in response to contact offluid 54 with fluid 50. It should be understood that other types ofcoloring mechanisms may be used to provide a visual indication of impactdetection. For example, in some embodiments, fluids 50 and 54 may beselected such that a chemical reaction resulting from contact of fluid54 with fluid 50 causes a change in color or discoloration of fluid 50.As will be described in further detail below, in response to tubeassembly 16 experiencing or being subject to a predetermined level ofimpact or acceleration event, a droplet or portion of fluid 54 lands onand/or contacts fluid 50, thereby mixing with fluid 50 and causing achange in color or discoloration of fluid 50 to visually indicate impactdetection.

In some embodiments, fluid 50 is selected having a viscosity greaterthan a viscosity of fluid 54 such that a droplet or portion of fluid 54is released and/or migrates toward fluid 50 in response to apredetermined level of impact or acceleration event instead of fluid 50migrating or being released toward fluid 54. For example, FIG. 3 is adiagram illustrating impact indicator 10 of FIG. 2 in response toexperiencing or being subject to an impact or acceleration event (e.g.,in direction 60 or at an angle thereto having a directional vectorcomponent in direction 60). Referring to FIGS. 2 and 3, in response to adroplet or portion of fluid 54 contacting fluid 50, the droplet of fluid54 begins mixing with fluid 50 and causes a color change ordiscoloration of fluid 50, thereby providing a visual indication ofimpact detection. The impact sensitivity of impact indicator 10 (i.e.,the level of impact or acceleration causing fluid 54 to be released andland on or contact fluid 50) may be controlled at least by the borediameter of internal cavity 40. As the bore size/diameter of cavity 40is reduced, a higher magnitude of acceleration is generally needed torupture a meniscus 62 of fluid 54 in contact with an interior surface 64of tube 30 and release fluid 54. For example, there are generally twofactors that influence fluid 54's response to acceleration—viscosity andsurface tension. Viscosity influences a fluid's ability to quicklydeform and change shape. Surface tension influences a fluid's affinityand adhesion to itself or an external surface. There is generally afinite range over which the viscosity of a fluid can be varied andsignificantly affect the activation or impact sensitivity. For example,in some embodiments, this range may be approximately between twentycentistokes and eighty centistokes, depending on the internal borediameter of cavity 40. However, it should be understood that otherviscosities or viscosity ranges may be utilized based on a selected boresize of cavity 40. In some embodiments of the present disclosure, fluid54 is selected such that higher accelerations are required to rupturemeniscus 62 while using a bore size of cavity 40 that promotes ease ofmanufacture. In some embodiments, the target bore size of cavity 40 isbetween 0.025″ and 0.085″ to provide ease of manufacture and highyields; however, it should be understood that the target bore size ofcavity 40 may be greater or smaller.

In some embodiments of the present disclosure, three classes of fluidsmay be utilized for fluid 54: a) synthetic hydraulic fluids; b) siliconeoils; and/or c) polypropylene glycol. These fluids promote higher impactsensitivities. For example, synthetic hydraulic fluids were originallydeveloped as a non-flammable alternative to oil-based hydraulic fluid.Synthetic hydraulic fluids are available in various controlledviscosities. Many synthetic hydraulic fluids have a very high viscosityindex. Viscosity index is a number that characterizes how the viscosityof a fluid changes due to temperature changes. Viscosity index iscalculated from the measured viscosity at 40° C. and 100° C. using ASTMMethod D 2270. Synthetic hydraulic fluids are stable and have moderatelylow freezing points.

Silicone oils (polymerized siloxanes) are generally considered not to besilicone but rather silicon analogues of carbon based organic compounds,and can form (relatively) long and complex molecules based on siliconrather than carbon. Chains are formed of alternating silicon-oxygenatoms ( . . . Si—O—Si—O—Si . . . ) or siloxane, rather than carbon atoms( . . . C—C—C—C . . . ). Other species attach to the tetravalent siliconatoms, not to the divalent oxygen atoms which are fully committed toforming the siloxane chain. A typical example is polydimethylsiloxane,where two methyl groups attach to each silicon atom to form(H3C)[SiO(CH3)2]nSi(CH3)3. The carbon analogue would be an alkane (e.g.dimethylpropane C5H12 or (H3C)[C(CH3)2](CH3)). Silicone oils have anextremely high viscosity index and are available in controlledviscosities. Silicone oils are very inert, stable and have very lowfreezing points.

Polypropylene glycol or polypropylene oxide is generally considered tobe the polymer of propylene glycol. Chemically, polypropylene glycol isa polyether. The term polypropylene glycol or PPG is reserved for a lowto medium range molar mass polymer when the nature of the end-group,which is usually a hydroxyl group, affect polymer properties. The term“oxide” is used for a high molar mass polymer when end-groups no longeraffect polymer properties. Polypropylene glycol is available in variousmolecular weights, which in turn provides for various viscosities.Polypropylene glycol also has a very low freezing point, is easilycolored, and has a moderate viscosity index.

Thus, in some embodiments of the present disclosure, synthetic hydraulicfluids, silicone oils, and/or polypropylene glycol may be selected invarious controlled viscosities for fluid 54. Further, synthetichydraulic fluids, silicone oils, and/or polypropylene glycol may also beblended to form fluid 54 having a precise desired viscosity. Thus,embodiments of the present disclosure enable the selection and/or use ofdifferent particular viscosity fluids that may be used with a singlecapillary tube bore size to provide a variety of different impactsensitivities for impact indicator 10. Thus, for example, in someembodiments, one capillary tube bore size for cavity 40 may be selectedand/or used while changing the viscosity of fluid 54 to produce avariety of impact sensitivities for the one bore size, thereby reducingthe number tube 30 bore sizes that need to be purchased/manufactured andalso increasing the volume of the single bore size that may bepurchased/manufactured (reducing the cost of material).

Thus, in operation, the bore size and/or viscosity of fluid 54 and/orfluid 50 are selected such that a predetermined level of impact oracceleration event is needed to effectuate a rupture of meniscus 62relative to fluid 54 to cause a droplet and/or portion of fluid 54 to bereleased toward and contact fluid 50. For example, referring to FIGS. 2and 3, because the viscosity of fluid 50 is greater than a viscosity offluid 54, in response to a sufficient magnitude of an impact oracceleration event, meniscus 62 distorts and/or ruptures causing adroplet and/or portion of fluid 54 to be released or migrate towardfluid 50. In response to a droplet or portion of fluid 54 contactingfluid 50, fluid 54 causes a color change to fluid 50 to thereby providea visual indication of impact detection. The spacing, separation and/ordistance between fluids 50 and 54 in a non-activated state may also beselected corresponding to a desired impact sensitivity or activation ofimpact indicator 10. For example, depending on the bore size of cavity40 and/or the viscosities of fluids 50 and/or 54, the amount ofseparation between fluids 50 and 54 by fluid 58 in a non-activated statemay be selected to accommodate a droplet and/or portion of fluid 54contacting fluid 50 in response to a predetermined level of impact oracceleration event.

In some embodiments (referring to FIGS. 1A, 1B and 2), portions of tubeassembly 16 may be covered or hidden from view (e.g., by clip assembly12) except for indicating portion 26. Thus, before activation, fluid 50visible within indicating portion 26 may depict a clear fluid or a fluidof a particular color. However, in response to experiencing or beingsubject to a predetermined level of impact or acceleration event, fluid54 causes a color change of fluid 50 such that the color change of fluid50 is visible within indicating portion 26 to provide a visualindication of impact detection. For example, if fluid 54 is colored witha red dye and fluid 50 is initially a clear fluid in a non-activatedstate, the red dye of fluid 54 may mix into fluid 50 in response toimpact detection, thereby causing fluid 50 to become colored red tovisually indicate impact detection. As described above, indicatingportion 26 may comprise an unmasked portion of tube 30 while remainingportions of tube 30 are masked such that indicating portion 26 comprisesa window or viewing area for visual impact detection indication.

Thus, embodiments of the present disclosure enable a very small impactdetection device to be manufactured and used with products that havevery little unused space available for incorporating an impact detectiondevice therein. For example, the general designs of handheld devices(e.g., mobile telephones, personal digital assistants, cameras, tabletor notebook computers, etc.) are such that there is very little unusedspace within the devices. The extremely small size of the impactindicator embodiments of the present disclosure enable a significantadvantage when an internal mounting within the handheld device is used.Internal mountings are typically used where a review of the deviceoccurs to determine warranty claims. The passive visual nature of theimpact indicator embodiments of the present disclosure enable them to beused without any electrical integration, thus there are no electricaldesign actions required by the handheld manufacturers. Further, in someembodiments, tube assembly 16 may be mounted directly to internalstructures of a handheld or other type of device. For example, in someembodiments, tube assembly 16 may be formed having masked portionsadjacent to indicating portion 26 such that tube assembly 16 may beindependently secured within a handheld or other type of electronicdevice (i.e., without clip assembly 12). In other embodiments, anothertype of clip assembly or attachment device may be used to secure tubeassembly 16 within the device. Thus, during repair and/or evaluation ofthe handheld device, impact detection may be readily observed/detectedby evaluating the color of indicating portion 26 of tube assembly 16 todetermine whether the device may have been dropped or otherwisesubjected to an impact or acceleration event.

FIG. 4 is a diagram illustrating a target impact sensitivity zone forvarious embodiments of impact indicator 10 according to the presentdisclosure. FIG. 4 illustrates a graph depicting acceleration (g level)versus time (in milliseconds), where “g” represents the accelerationlevel due to gravity (e.g., 9.8 m/s²). For many types of handheldelectronic devices (or even other types of devices/components),relatively high acceleration levels are experienced over a relativeshort time period (e.g., several milliseconds). Such devices aregenerally manufactured to specifications which require the device towithstand certain high levels of acceleration experienced over a shorttime period (e.g., moderate disruption of operation) while accelerationlevels above some threshold may result in inoperability of the device.Embodiments of the present disclosure enable a small, compact impactindicator that may be used with such electronic devices to determinewhether the electronic device has been subjected to a level ofimpact/acceleration exceeding some threshold such that may havecontributed to an inoperable condition of the device.

Referring to FIG. 4, by reducing a bore size of cavity 40 of tubeassembly 16 and selecting certain viscosities for fluid 54 and/or fluid50, the impact sensitivity of impact indicator 10 may be configured tobe within a desired impact sensitivity or activation zone, such as animpact sensitivity or activation zone 70 depicted in FIG. 4. Forexample, in some embodiments, a bore size of cavity 40 may be configuredto be between 0.025″ and 0.085″ and a viscosity of fluid 54 may beselected to be between twenty centistokes and eighty centistokes. Atsuch bore sizes of cavity 40 and viscosities of fluid 54, impactindicator 10 may be configured for an impact sensitivity or impactactivation corresponding to the impact sensitivity zone 70 asillustrated in FIG. 4, thereby providing an impact indicator that isactivated in response to high acceleration levels experienced overrelatively short time periods. For example, by selecting a certain boresize of cavity 40 and/or a certain viscosity of fluid 54, an impactsensitivity or impact activation level for impact indicator 10 may beset for activating in response to at least a 400 g-force valueexperienced for a two millisecond time period, or in response to atleast a 300 g-force value experienced for a time period between 1.6milliseconds and 5 milliseconds. It should be understood that variousimpact sensitivity or activation levels may be configured for impactindicator 10 by adjusting a size of cavity 40, a viscosity of fluid 54and/or fluid 50, and/or a size of separation between fluids 50 and 54 byfluid 58 to obtain impact sensitivity or activation levels within zone70. It should also be understood that impact indicator 10 may also beconfigured to impact activation at g-levels/time periods outside thoseindicated by zone 70

Various methods may be employed to manufacture impact indicator 10. Forexample, in some embodiments, a syringe or other instrument may be usedto first introduce or dispose fluid 50 within cavity 40 at end 52 oftube 30 from or through end 34. A syringe or other instrument may thenbe used to introduce or dispose fluid 54 within cavity 40 spaced apartfrom fluid 50 from or through end 34. Plug 36 may then be inserted intoend 34 of tube 30 to seal or close cavity 40. In other embodiments, tube30 may be open at each end such that fluids 50 and 54 may be introducedor disposed within cavity 40 from respective opposite ends of tube 30.Tube 30 may then be sealed (e.g., sealing cavity 40) by utilizing a plugat both ends of tube 30. It should be understood that various othermethods may also be used to produce or manufacture impact indicator 10.

FIG. 5 is a diagram illustrating another embodiment of impact indicator10 in accordance with the present disclosure. In the embodimentillustrated in FIG. 5, impact indicator 10 is depicted in anon-activated state. In FIG. 5, impact indicator 10 includes tubeassembly 16 with fluid 50 located near or at end 52 of internal cavity40 of tube 30. In the illustrated embodiment, a fluid 80 is located nearor at an opposite end 56 of internal cavity 40. Fluid 80 may comprisethe same type of fluid as fluid 50 or may comprise a different type offluid. Fluid 54 is located within cavity 40 between fluids 50 and 80.Further, fluid 54 is spaced apart from fluid 50 and fluid 80 withincavity 40 in an inactivated state of impact indicator 10 by separatingfluid 58 and a separating fluid 82, respectively. In some embodiments,separating fluids 58 and 82 comprise a gas such as, but not limited to,atmospheric air; however, other types of gases or fluids may be used. Insome embodiments, fluid 54 comprises a coloring fluid or dyed fluid, andfluids 50 and/or 80 comprise a clear or other type of fluid that issoluble or miscible with fluid 54. In some embodiments, fluid 54 mayinclude a colored dye such that the colored dye discolors and/orotherwise causes a color change to fluids 50 and 80 in response tocontact of fluid 54 with either fluid 50 or 80. It should be understoodthat other types of coloring mechanisms may be used to provide a visualindication of impact detection. For example, in some embodiments, fluids50, 54 and 80 may be selected such that a chemical reaction resultingfrom contact of fluid 54 with either fluid 50 or 80 causes a change incolor or discoloration of respective fluid 50 or 80. As will bedescribed in further detail below, in response to tube assembly 16experiencing or being subject to a predetermined level of impact oracceleration event, a droplet or portion of fluid 54 lands on and/orcontacts either fluid 50 or fluid 80 (e.g., depending on a direction ofimpact or acceleration event), thereby mixing with fluid 50 or fluid 80and causing a change in color or discoloration of fluid 50 or fluid 80to visually indicate impact detection.

In some embodiments, clip assembly 12 and/or tube assembly 16 may beformed to create indicating portion 26 relative to fluid 50 and anotherindicating portion 84 relative to fluid 80 such that portions of tubeassembly 16 may be covered or hidden from view except for indicatingportions 26 and 84. Thus, before activation, fluids 50 and 80 visiblewithin respective indicating portions 26 and 84 may depict a clear fluidor a fluid of a particular color. However, in response to experiencingor being subject to a predetermined level of impact or accelerationevent, fluid 54 causes a color change of fluid 50 or fluid 80 such thatthe color change of fluid 50 or fluid 80 is visible within a respectiveindicating portion 26 or 84 to provide a visual indication of impactdetection. In some embodiments, fluids 50 and 80 are selected having aviscosity greater than a viscosity of fluid 54 such that a droplet orportion of fluid 54 is released and/or migrates toward either fluid 50or fluid 80 in response to a predetermined level of impact oracceleration event (depending on impact or acceleration event direction)instead of fluid 50 or 80 migrating or being released toward fluid 54.Thus, in response to a sufficient magnitude of an impact or accelerationevent, depending on a direction of such impact or acceleration event,meniscus 62 or a meniscus 86 of fluid 54 distorts and/or rupturescausing a droplet and/or portion of fluid 54 to be released or migratetoward fluid 50 or fluid 80. In response to a droplet or portion offluid 54 contacting fluid 50 or fluid 80, fluid 54 causes a color changeto respective fluid 50 or fluid 80 to thereby provide a visualindication of impact detection.

Thus, embodiments of the present disclosure enable impact and/oracceleration event detection utilizing a passive, small/compactindicator. Further, embodiments of the present disclosure enable impactand/or acceleration event detection over an increased range ofacceleration event conditions (e.g., g-levels experienced over shorttime durations), thereby facilitating use of the indicator 10 with avariety of types of devices. Further, embodiments of the presentdisclosure provide omnidirectional impact detection and indication.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present disclosure has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the disclosure in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the disclosure. Theembodiment was chosen and described in order to best explain theprinciples of the disclosure and the practical application, and toenable others of ordinary skill in the art to understand the disclosurefor various embodiments with various modifications as are suited to theparticular use contemplated.

What is claimed is:
 1. An impact indicator, comprising: a tube having afirst fluid and a second fluid disposed therein, wherein a viscosity ofthe second fluid is greater than a viscosity of the first fluid, andwherein, responsive to a predetermined level of an acceleration eventreceived by the impact indicator, at least a portion of the first fluidmixes into the second fluid to create a change in color of the secondfluid to provide a visual indication of the received acceleration event.2. The impact indicator of claim 1, wherein the first fluid comprises acolor different than a color of the second fluid in a non-activatedstate of the impact indicator, and wherein the second fluid is solublewith the first fluid.
 3. The impact indicator of claim 1, furthercomprising a third fluid disposed between and separating the first fluidfrom the second fluid in a non-activated state of the impact indicator.4. The impact indicator of claim 3, wherein the third fluid comprises agas, and wherein the first and second fluids comprise liquids.
 5. Theimpact indicator of claim 3, wherein an internal bore size of the tubeand an amount of separation between the first and second fluids by thethird fluid are selected to obtain a desired activation sensitivity forthe predetermined level of the acceleration event.
 6. The impactindicator of claim 3, wherein an internal bore size of the tube, anamount of separation between the first and second fluids by the thirdfluid, and the viscosity of the first fluid are selected to obtain adesired activation sensitivity for the predetermined level of theacceleration event.
 7. The impact indicator of claim 1, wherein aninternal bore size of the tube and the viscosity of the first fluid areselected to obtain a desired activation sensitivity for thepredetermined level of the acceleration event.
 8. The impact indicatorof claim 1, wherein the first fluid comprises a synthetic hydraulicfluid.
 9. The impact indicator of claim 1, wherein the first fluidcomprises a silicone oil fluid.
 10. The impact indicator of claim 1,wherein the first fluid comprises a propylene glycol fluid.
 11. Theimpact indicator of claim 7, wherein the viscosity of the first fluid isbetween 20 and 80 centistokes.
 12. The impact indicator of claim 11,wherein the internal bore size of the tube is between 0.025 and 0.085inches.
 13. The impact indicator of claim 7, wherein the internal boresize of the tube and the viscosity of the first fluid are selected toobtain a desired activation sensitivity of at least a 400 g-force valuefor a 2 millisecond time period.
 14. The impact indicator of claim 7,wherein the internal bore size of the tube and the viscosity of thefirst fluid are selected to obtain a desired activation sensitivity ofat least a 300 g-force value received for a time period between 1.6milliseconds and 5 milliseconds.
 15. An impact indicator, comprising: atube; a first fluid disposed within the tube; a second fluid disposedwithin the tube, and a third fluid disposed within the tube, wherein thethird fluid is disposed between and separates the first fluid from thesecond fluid in a non-activated state of the impact indicator, andwherein, responsive to a predetermined level of impact received by theimpact indicator, at least a portion of the first fluid contacts thesecond fluid to create a change in color of the second fluid to providea visual indication of the received impact.
 16. The impact indicator ofclaim 15, wherein the first fluid comprises a color different than acolor of the second fluid in a non-activated state of the impactindicator, and wherein the second fluid is soluble with the first fluid.17. The impact indicator of claim 15, wherein an internal bore size ofthe tube and an amount of separation between the first and second fluidsby the third fluid are selected to obtain a desired activationsensitivity for the predetermined level of impact.
 18. The impactindicator of claim 15, wherein an internal bore size of the tube, anamount of separation between the first and second fluids by the thirdfluid, and a viscosity of the first fluid are selected to obtain adesired activation sensitivity for the predetermined level of impact.19. The impact indicator of claim 15, wherein the first fluid comprisesat least one of a synthetic hydraulic fluid, a silicone oil fluid and apropylene glycol fluid.
 20. The impact indicator of claim 15, whereinthe first and second fluids comprise a liquid, and wherein the thirdfluid comprises a gas.
 21. The impact indicator of claim 15, wherein aninternal bore size of the tube and a viscosity of the first fluid areselected to obtain a desired activation sensitivity for thepredetermined level of impact.
 22. A method for manufacturing an impactindicator, comprising: disposing, within a tube, a first fluid;disposing, within the tube, a second fluid spaced apart from the firstfluid by a third fluid, the second fluid selected having a viscositygreater than a viscosity of the first fluid, and wherein, responsive toa predetermined level of impact received by the impact indicator, atleast a portion of the first fluid contacts the second fluid to create achange in color of the second fluid to provide a visual indication ofthe received impact.
 23. The method of claim 22, further comprisingproviding an internal bore size of the tube to obtain a desired impactsensitivity for the predetermined level of impact.
 24. The method ofclaim 22, further comprising providing the first fluid comprising atleast one of a synthetic hydraulic fluid, a silicone oil fluid and apropylene glycol fluid.
 25. The method of claim 22, further comprisingproviding an internal bore size of the tube, an amount of separationbetween the first and second fluids by the third fluid, and theviscosity of the first fluid to obtain a desired activation sensitivityfor the predetermined level of impact.
 26. The method of claim 22,further comprising providing the first fluid having a color differentthan a color of the second fluid in a non-activated state of the impactindicator, and providing the first and second fluids where the secondfluid is soluble with the first fluid.
 27. The method of claim 22,further comprising selecting the first and second fluids as a liquid,and selecting the third fluid as a gas.